Thalamic dementia and motor neuron disease.

A 46-year-old woman developed a progressive neurologic disorder over the course of 30 months which was characterized by profound dementia complicated by a motor neuron disorder that became evident 10 months prior to death. Postmortem examination of the nervous system disclosed extensive neuronal loss and gliosis of the thalamus, predominantly involving the dorsomedial nuclei, as well as severe degeneration of the corticospinal tracts, spinal anterior horns, and hypoglossal nuclei. The disease could not be transmitted to experimental animals by intracerebral inoculation of the patient's brain tissue. This case represents a unique dementing disorder, possibly familial, with associated motor neuron disease.